JPH0525204Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention is particularly suitable for applications in which the plunger is used in repeated reciprocating motion, and is a compression coil for urging the plunger to move in a direction away from the core when not energized. This relates to a solenoid with an improved spring shape.

2. Description of the Related Art A solenoid that is used by repeatedly reciprocating a plunger is used, for example, as a drive source for a switching device for switching between feeding and stopping in a weft feeding portion of an automatic loom that feeds out a weft by a constant length corresponding to the width of the woven fabric. It is used.

An example of this will be explained with reference to FIG. 1, which shows an embodiment of the present invention. In the solenoid 1 of this example, a core 5 is fitted into the upper end of a center hole 4 of a coil bobbin 2 around which a coil 3 is wound, and a cylindrical plunger 7 is fitted into the lower end so as to be freely slidable. A compression coil spring is fitted between the lower surface of the core 5 and spring receivers 8 and 9 fitted inside the plunger 7, respectively. This solenoid 1 is attached to the upper surface of a body 11 which has an insertion hole 12 which has an enlarged diameter device hole 13 on the upper end side.
The actuating pin 15 is fitted tightly into a bushing 14 fitted to the lower end of the plunger 7.
is fixed. When the solenoid 1 is not energized, the plunger 7 is urged downward by the elastic expansion force of the compression coil spring, and a stopper 17 is formed on the outer circumference of the plunger 7 and has a locking collar 16 housed in the bottom surface of the device hole 13. When the solenoid 1 is energized, the plunger 7 is attracted to the core 5 side against the elasticity of the compression coil spring and moves upward, and by repeating de-energization and energization, the plunger 7 moves up and down. The actuating pin 15 reciprocates between an operating position in which it protrudes by a certain distance from the lower surface of the body 11, indicated by a solid line, and a retracted position, in which it is retracted into the insertion hole 12, indicated by a chain line. ing.

The body 11 to which this solenoid 1 is attached is installed near the bobbin around which the weft is wound in the weft unwinding part of the automatic loom.
By energizing the weft and retracting the operating pin 15 to allow the weft to be fed out, and repeating the following steps: de-energizing the weft, causing the operating pin 15 to protrude and hooking the thread to stop the weft, The weft is supplied in fixed length increments.

Problems to be Solved by the Invention By the way, in the solenoid 1 as described above, the compression coil spring used to bias the plunger 7 downward has conventionally been provided with a coil portion formed by spirally winding a wire into a cylindrical shape, and a coil portion attached to both ends of the coil portion. , a cylindrical coil spring is used in which an end turn part that is perpendicular to the axial direction is connected with the coil part and the same diameter. However, in such a cylindrical coil spring, when the plunger 7 is attracted to the core 5 side and elastically compressed, the wire at the end of the coil part is struck against the end turn part, and as described above, the plunger Since the reciprocating motion of step 7 is repeated, the strands are likely to wear out. When the strands wear out, the spring constant of the coil spring changes, which changes the biasing force and load on the plunger 7, causing a shift in the timing of the movement of the actuating pin 15, and changing the payout length of the weft thread. There were some drawbacks that brought about many negative effects.

Means for Solving the Problems The solenoid of the present invention was devised in view of the above points, and the solenoid of the present invention is designed to separate the plunger from the core by the elastic expansion force of a compression coil spring installed between the plunger and the core. In this solenoid, the plunger is biased to move in the direction of separation, and magnetized to attract the plunger toward the core against the biasing force of the compression coil spring. It is characterized by having a shape in which an end turn portion having an outer diameter smaller than the inner diameter of the coil portion is connected.

Functions and Effects of the Invention The compression coil spring of the present invention has its end turn part escaping radially inward from the coil part, so when the plunger is attracted to the core side and elastically contracts, The strands at the end of the coil part simply wrap around the outer periphery of the end-turning part and are not struck against the end-turning part, and since the above-mentioned end-turning part escapes inward, the ends of the coil part It is also possible to shift the strands of strands outward in the axial direction so as to surround the outer periphery of the end-turning part, and by doing so, the pitch between the strands can be increased while keeping the effective number of turns in the coil part the same. This also prevents the strands of the coil portion from coming into contact with each other.

In other words, even if the compression coil spring is repeatedly compressed and compressed, there is no risk of the strands being worn out by the impact pressure.
Changes in the spring constant due to wear of the strands are reliably prevented. Therefore, the biasing force and load on the plunger can be kept constant, and the forward and backward movements can be performed at constant timing over a long period of time.

Further, since the end turn portion of the compression coil spring escapes inward in the radial direction with respect to the coil portion, there is no need to take up any extra storage space.

Embodiment Hereinafter, an embodiment of the present invention will be described based on the accompanying drawings.

In this embodiment, the compression coil spring 21 for downwardly biasing the plunger 7 of the solenoid 1 described in the prior art section spirals the wire 22 into a cylindrical shape, as shown in detail in FIG. Wound coil part 2
End turn portions 24 at both ends of 3 are perpendicular to the axial direction.
It has a shape in which the outer diameter is smaller than the inner diameter of the coil portion 23, and the core 5 has a shape smaller than the inner diameter of the coil portion 23.
Both end turn portions 24 are externally fitted onto the protrusions 8a and 9a of the spring receivers 8 and 9 which are fitted into the lower surface of the plunger 7 and inside the plunger 7, respectively.

This embodiment has such a structure, and the end turn portion 24 of the compression coil spring 21 is formed to escape inward in the radial direction with respect to the coil portion 23. As shown in Figure 3,
When the plunger 7 is attracted to the core 5 side and the compression coil spring 21 is elastically contracted, the strands 22 at the end of the coil portion 23 simply wrap around the outer circumferential side of the end turn portion 24 and are struck against the end turn portion 24. There is no Furthermore, since the end turn portion 24 is formed to escape inward, it is also possible to shift the strands 22 at the end of the coil portion 23 to the outside in the axial direction so as to surround the outer circumferential side of the end turn portion 24. By doing so, the pitch between the strands 22 can be increased while keeping the effective number of turns in the coil part 23 the same, and the pitch between the wires 22 can be increased.
It is also possible to prevent the strands 22 from hitting each other.

Therefore, there is no risk that the wire 22 will be worn out by the impact pressure, and the spring constant of the compression coil spring 21 will not change midway due to wear of the wire 22. As a result, the downward force acting on the plunger 7 and the load during upward movement are maintained constant, and the operating pin 1
5 can be moved back and forth to the operating position or the retracted position at the same response speed at all times, and the weft can be fed with a constant payout length.

Further, since the end turn portion 24 of the compression coil spring 21 escapes inward in the radial direction with respect to the coil portion 23, there is no need to take up any extra storage space.

Note that the present invention is not limited to the solenoid 1 used in the switching device for switching between feeding and stopping the weft feeding portion of an automatic loom as shown in the above embodiment, but is also applicable to other devices in which the reciprocating motion of a plunger is frequently performed. The same applies to solenoids in general.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the overall structure of an embodiment of the present invention, FIG. 2 is a partially enlarged sectional view when the device is not energized, and FIG. 3 is a partially enlarged sectional view when it is energized. 1... Solenoid, 5... Core, 7... Plunger, 8, 9... Spring holder, 21... Compression coil spring, 22... Element wire, 23... Coil part, 24...
Round part.

Claims (1)

[Scope of utility model registration request] The plunger is urged to move in a direction away from the core by the elastic force of a compression coil spring installed between the plunger and the core, and by excitation, the plunger is moved against the urging force of the compression coil spring. In the solenoid configured to attract air to the core side, the compression coil spring has a shape in which a cylindrical coil portion is coupled with an end turn portion having an outer diameter smaller than the inner diameter of the coil portion at both ends of the coil portion. Features a solenoid.